1. Field of the Invention
The present invention relates to a display device in which a plurality of pixel circuits are arranged on a substrate and each of the pixel circuits displays a gray level.
2. Description of the Related Art
There is a display device, exemplified by a liquid crystal display device, in which pixel circuits are arranged in matrix on a substrate and each of the pixel circuits displays a gray level. In the display device, the pixel circuits in each column are connected to a corresponding image signal line. The image signal line is applied with a gray-level potential corresponding to a display gray level from an image signal line driving circuit, and the image signal line supplies the potential of the image signal line in succession to the pixel circuits connected thereto. Meanwhile, with the recent increase in resolution and frames per second, each pixel circuit is applied with the potential for a shorter period (horizontal period). This causes a troublesome phenomenon that, when the image signal line is applied with the gray-level potential, a large difference occurs between a target gray-level potential and a potential of the image signal line reached in the horizontal period. This phenomenon changes a potential to be applied to the pixel circuit with the result that, for example, a different gray level from an intended gray level is displayed.
A known method for reducing the phenomenon is a technology called overdrive. Ina display device that implements the overdrive, the image signal line is supplied with a potential obtained by correcting the gray-level potential. More specifically, the potential obtained by correcting the gray-level potential is generated based on a gray-level potential to be supplied to a certain pixel circuit and a potential of the image signal line prior to the timing of supplying the gray-level potential. The generated potential is then supplied to the image signal line. When the thus corrected potential is applied to the image signal line in a horizontal period 1H, a potential of the image signal line comes close to the gray-level potential more quickly as compared with when the gray-level potential is applied as it is. At the end of the horizontal period 1H, the image signal line has a potential closer to the gray-level potential. Further, in the display device that implements the overdrive, a value of the potential obtained by correcting the gray-level potential is calculated by a control board that is provided separately from a liquid crystal display panel. The calculated value of the potential obtained by correcting the gray-level potential is input to the image signal line driving circuit from the control board. The image signal line driving circuit generates a potential based on the value (performs digital to analog conversion), and applies the potential obtained by correcting the gray-level potential to the image signal line.
Japanese Patent Application Laid-open No. 2008-209890 discloses a display device in which a potential obtained by correcting a gray-level potential as described above is supplied to the image signal line.